SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0274fde71486a54a92fca56a923c16ac89cd923656fcbc71001a020937ede8c' 
  AND token = 'haEAMZnfb/NE8cS/Bn7ldvmH8snJzKcjQRHTZl47u2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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