SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '504c5348abb4af8cb30306dbcb177506c932c10ed60b7e9c990182645bd9cbba' 
  AND token = 's3GbHfUpFn6iJnuV0q0Os8qsPfum6DFsSsVOZtMAFVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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