SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc61966da5dfd88247c67660378476d9f57bb609823697c473a5a14a7f154673' 
  AND token = 'tWVq4B5Wcqbz1LBXygUIZNE8Zxte7ODOHbSLn8YU6q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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