SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '612c1d2d307e6f1e39205911741a136f3e69126f9854e985e9bf5b5d1947b3d2' 
  AND token = 'OtBuVzuvsTHtJtCbkHJtUIHWRFZjcsG3AEfIL4sKXAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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