SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5c55281d116a9917c6c897ec6fedfe60f44c3484e32f365d76165cc5d8e5c14' 
  AND token = 'HZf7bFgD5rKUdpIeR/Ngg353XHsseezOnyEl4KW8ccA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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