SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd97139a79e04a203206d7f34ed6048a0a4d9f216baf94ca14bd977cab350c463' 
  AND token = 'zPk3uQBPj58YOgVhWG0QujeiNzEiKw483+dP1HTkBig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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