SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf95c140e983c363945d1700b3e1746436da7dd3a349475489e6c1f28f96904e' 
  AND token = 'mQhDXLb+GT+jgMv7qvjd5qp65q9FLJA6ez1HCG88kP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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