SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b514299ed6a71479f894b150fe09007b8c3daf02432e2c8e25a81013bae7b258' 
  AND token = 'CzZZH4N7tZod/uI2BQ9kfJjmsoruxYE01wrZ+g6kGks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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