SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e3aafdda200bfa25fad5a22692cc3dcc650ce1f8e87f5a10cb7b96ff049d1a9' 
  AND token = 'n4MEYiDy01GXszjp6C6ZpJbIMJwhq5MHHY9hZ3rbxmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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