SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99e13230e326ece839a978001771601fedbf0be3c563fd6a9426132ed13b1cc2' 
  AND token = 'wPJ9uCVzBAPWpuqWx98Dp52+7+sxnl+EahnMagDZikg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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