SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3c8c6bfcb879f62f3f8d7dc049989d855805fdacf5315a711cec317728fa6382' 
  AND token = 'Xf0xnmGyd7hJwRGJew8XamZBYAMCBtXRj43mhS1zWS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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