SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6830dd8993753c93a241d5fc1fe973a920996828d6126c8d099854f5bd43ba41' 
  AND token = 'jwa+yr4cBl1TKVBNv91THBu3lgZjvTXqvtXPR9oFuLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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