SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c5912c4916c73538261d797faaf1338b333083da82854b97465876531bad075' 
  AND token = 'Y9eDXDmnIk0Tk6nXWfcWmYLpLYcXXV8YWkycRvXo48c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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