SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '925499203554b3271d6c412fa8624cfc943c45018a951f3ba05b0ed2784eab76' 
  AND token = '79ATrE4O6T5EyNiTWTnb3gQL4BArbagIlsQG/1CyaCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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