SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dce33bd0c979b0f1439b44d90a6e78902c62a5d937326337d090515ff06c0053' 
  AND token = 'raxOZD3oQw8VGTMzaPn7AlUvr7CtQUl8vyHQjF/tEeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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