SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23575655b8390321fffde8ab77d3fb2ca0a060e847f27a012a9682e8d10d5554' 
  AND token = 'tf0Js1atI1oXyKfeaAPqIlipniZFuowkETzEeN7GR80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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