SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd843d89fd7175e65280848cb0af3a423b7cb890252ba87169695593f53bdc29' 
  AND token = 'B24w+EwlVXIz9+AAoBGO49F1/n7fV2WKnv8PxZKamks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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