SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fe1fb4e6eba608d3b5e863d29b45b8ab925420e9f75310da68076b4cdf7bb8c' 
  AND token = 'e+YDLJKh/ZzFRdV1kfH8iOOhDZcWmfT3guWRgFGzX14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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