SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d4372ff8d6d4386937c900c7a50e48733a2bcc68ab73717762f59591fae920b' 
  AND token = 'xL/0f1jhPNdiO8ZkrbI2KAhDahJFQvimPbFxNq9Z0a4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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