SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '713310ae6dcb41d3b6ed6856f9d7827cb00a5cbe85d208ac035d09f46bd13089' 
  AND token = 'YcMSuRQsig1KiNoaZxBj2JpN6hvtc4CQg3+wYZb/Bjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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