SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6b6e7048b8dc020926281af205f19cc0b7a567c91dbe8732f0afb7238cfbba30' 
  AND token = 'BmyDfWR1pc3unxxlabmrRMHEuifDOPZKyteUk/m9Ik4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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