SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '774bb30701cda842884fa7e761dbe82da76375b6be70f211dc59f3cf839b0d61' 
  AND token = '2yNGQZffrBhmr4zTQV3cv+B6rKoKWC/TCdqTPZPkrYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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