SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a12711d907f62098a767630049d6afca0e80b43945663a003b4b2fc2dea256cf' 
  AND token = '4MNttjquFo+mQPwOKWeaoJroog0kURFhXZw+4aB63Uc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}