SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1598349a412303796b9858ec1df6c1335f6fddf2316434c2c056cdfbe8bf63de' 
  AND token = 'TmMvnqA16L968W9ysF2rivECkgHI62zvPbu/Av8vUxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}