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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c251b1ae078d2cfb7f94762c75f4e5f03ec0d251bdc02278c19348abbeb97279' 
  AND token = 'n+DS6UiDNSq97OoJUV97r18+lcQhlx6bRQQy1a3dQ7Y=' 
  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"
    }
  }
}