SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e51b16f42ef83c7d6ae3a1309995e6df6c2c42dd4322a4fe569eb5d22ce435a4' 
  AND token = 'viEyUhLbfx+WTaCAKmKdtdsya0Q2k/LDz7nJWiCyRmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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