SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '416d8677827308bc6ef74e3343917dc53b312f9c41025e4ac2ef6747fd5d70dc' 
  AND token = 'a4hFQE9jIuAwvlh4ksVSuAseLW8rzDnUbNfxxLBtG58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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