SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd70d9d6b07648843167f25fc58327de308a8f352a50b90852255be1911283ab4' 
  AND token = '8jAJWcQSvOsbGEWgaU+DEevmoVckiIHpDzIDk7bQMYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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