SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35e365b73bfecb5e2585a445cd624d40192b93cebe9ce950b48b0378fe7b03b5' 
  AND token = 'njvIDx0TEhjQsc7qb9Bs7QAGqCOVEZ2HlyB76hxEFWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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