SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea68f083c60b304c284a337cfd116b8207e89cef765a343fee44f7b6af6e187c' 
  AND token = 'pFMJjQXs6bcix/ROCV+a19Mk/dUn8Eff2EMT5hKgHVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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