SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '89f8f0e8558b2d797185a897cfee1aa44f67b62aa85125fa05626d225bb4205a' 
  AND token = '0X/LVWrxDOkwdR14XhYBKoN4rOgV1Rd7PLqVmXHCjDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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