SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80349988795e2c6fe9720c754a7811413e2274ddab30a73d77691f2853a5fbdd' 
  AND token = 'HtsS/lMl4djFvOdBf/2tm+EAUhrZYs6u79us9fbuovY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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