SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b58812f87bba9b61057a3165107179ffca998cbd56a60b2d160ffdcd6dc6bd35' 
  AND token = 'EIyWYeURhp44vwvhW6G4KMx7EMMz4JTJUTabTb3hGZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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