SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '990ea4b52c7bc7854da5593610e6c4e049c00649f20eb625caf6770096a9e9fe' 
  AND token = 'WbeOJrioJRkvzLiVufMGSCLXrRCNrbnk362iKoG20i0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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