SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9237c23b1aeb8357a194646e2c4ef11942edb63e5bc51b698c10f877ab66d904' 
  AND token = 'uZ/jkfF1GUt+KWtz/Z9sqvis5ZoNQ2nEohb7TV6C4iE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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