SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f27c312a3ee12b40d1be9165a0082f5f906ec50ab6f330c1a8ba945441a190b' 
  AND token = 'kn9V381lgiytJnE2kc5GcHqdXWdDXmgRNRQQJTjMV7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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