SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ae32fa6c37c0e15cdd27158d8c1bf3241bd787b30cc9bf433259a6cd058c87' 
  AND token = 'YXVTbCpFGWuxJoKXdBKvemqRYxnoTfq6Nb1LFg5UlSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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