SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '346b5f4a4b6882abc50c9fd1043b5aa1d9a917ff8a051e473a8e7ed9cd28224a' 
  AND token = 'X9/9G6K5TUofj5ztCmzVQauzptJ6PF5RZnzbq9o14BE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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