SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4fc253f04bea197fd915a290e1f7f283744a93663641ad58bf9e89459d7ca5b' 
  AND token = 'MHHv9BiZ1obeIAnlqfGSWpr6DKkLj/geVjlzqD/CxIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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