SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a6a345cea7552981fabd36cbbf8a43b5ed7f62342ed4579b491de8639d778872' 
  AND token = 'jAj20SmXBcTZ7xCVuT/x28R/f/A64zzHqtKq/sC4Ds0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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