SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'daec78bd7d4d81445023d33539b61b64718fe64942336d7edebeaaa3f9ce42a2' 
  AND token = 'KM7r9aR4yfejC7uA1aUoW627YIfTxX3z3Rl07z9SrrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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