SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12ace31f950e5b934281a05b5191e654899ffa55a94c1c1322ed4ad42b04ce0d' 
  AND token = 'uckDI+KmG/2aZ8nr4cNUhOv1kxvWUlocjQjPZ7ajOFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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