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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55eb4246a8af290573d5dc4ef76b6acc28aa5d8b6996d3b05f37f0ae5c45a00d' 
  AND token = 'j6Pa+Txa39xVKd9mFkkgcbPY6azLP5D5XLDdBB3cPlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}