SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5de886f11eb0c9b6f9d2b49292eb67477f49f49b2538f65dea0b518353a5041' 
  AND token = 'dH7t//iigwazsRIz/vpgdQ3mVDSexaVxIJWh/ix1fyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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