SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d7ffdf0293a89c494782ae0b6a39db184698b137d9057313f3b50e2ccb42445' 
  AND token = 'VAz+HKqT0ZosAQt0ZL6wIW5sZ4vKw4d/RJzSUdfFgjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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