SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ba776d032d6c0b74dec7cf8530010ff60795b1910116d1b5fc1df2eb17c58857' 
  AND token = 'c/Iomm06yYwDz18W+TupSDtROe2ORWk+noaaWtkuKP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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