SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ce987b6f457e4079738542dc2d916266c0f50fafcd7b1faeb4ac87409abe67b' 
  AND token = 'ADup+TihEIPzXxw8B8FYkn7SWHpPeMKIJgZgN4qTh0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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