SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '955b59b5bf3820f1ff42d9ed20b2d1c046e485bbe2006156adcda420fcec0fca' 
  AND token = 'GL0nLwS+urXoozsHvvvE9xrgtUBplYpY6lsm2n80R6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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