SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd112b376a833a951d9a35b2a86c4b2b918bac72544fadb03e9bee66f5eb078f2' 
  AND token = 'aQym1VpBYNCFZO/55YAUx3tLtMLkIqhOD0TGjVybgK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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