SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebc02095218fc166fa453aca26f353b171a7ed2a6253738e4bcce38db8ecd9ff' 
  AND token = '6Kxfin4BGb7K6RFdx1PUBba3xbl5pcHHyeVA9Rn0CZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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