SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd4443ffa50b337bfbe8d836735bea971af6067d90f56259edb3bb2f1ee2b5649' 
  AND token = '520ky4jn8sfKesvT+AGmC1auPVUPHpkFTBfJw7xg8PU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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