SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '173176e657b3326cdfbda0019af37ece057b4a89721fc4b623218a1ca59dd227' 
  AND token = 'UHwRE6YDWsGHU42/8soV3dQJhIzWIkGxOhcjWh4bJNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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