SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87ef1bcedc6c647df81853392e9657c3af7f589ff0b9e36753e024c7afe73ece' 
  AND token = '/m+KW6uTjJbKK7Wg+OnZDJgu7ZC1E3qHGz3SxIcm670=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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