SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afcd1077c7e99e06e5470d54e1ebd3b02f6bca8e267fec1fe60596b346fbb6d3' 
  AND token = 'FB18CCOEqyztsNgEjGhgoqfnt5VU/ZX9fTkHbbwqeNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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