SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9898d94b3c759cfd7b1da83451f8c24e30bf5db38ffdc622df24631f58ab3fa2' 
  AND token = 'WdKnPtS9pFvDVOu580O90fst99d4Ix6/GLjw7JV1yN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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