SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b7d34d316a672e348ecb67b19d2ca1489759ffa7282724a13cdbdf6191ca49b' 
  AND token = 'w3kLqY+WmhayROzZFW4fjOcfbnT6bnNEUC1CvTKJfBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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