SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42f7981cf0228cb759363ad03ab7d69a044e667ed104ca53b578a8a41bfe256a' 
  AND token = 'a5AWIYL/Pq9O/gCo1jPlMC1f7jnCq7tZsHzwITUZwRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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