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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c49a264e9cbc3b9c6fd41e6136f2f0b2f383b1da9a7865f186a99e5570aa0ef2' 
  AND token = 'exutqV2WrnARZt/0vPW90YjrGOvl2W4jMKXe+1bVSw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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