SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'db4139a3f668de1f3061f1a41818bb5e8a898f195db35f9783709c894368f89d' 
  AND token = 'AGK6I2B8nTYrZH6j3jDD+tv2XQ8Y6w0zhTsOKpbzoAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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