SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7166106f7b2c4a3332cc5e76d3d88894febb80a732be2aad5d8b15946ce7f583' 
  AND token = 'KRw8oCFKjSDImzYK5Zrk2CCaiY/UAHroECiPL5SwIMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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