SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '082a50b5b2b24cdf3c0a7d5151174e7570a693d6a536653e4f92d04bf8c01089' 
  AND token = 'jDXDujYquD9Fe8x1216hGkmOV9m/kIrV/ZRHw7lOQFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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