SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b5ef879a9eb2e3dffd31a3f7bd65bb1e091d80111fa67251a94239e6da4b62b9' 
  AND token = 'FUE/seOoOvVLA7hB6PjqtqkoYMb6M/tZ488848ueFQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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