SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '677c97a2c9d9080bda9efbc2e2f68457e65401e5ee25d82e74ce06a45124201c' 
  AND token = 'DZuYqdwDc4FognbP99bXmmsmimQCpgnGP+NZUzKG7DU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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