SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd319544f346a5e6b4d8d0881b15fd5e1b4892e1fb770a63457a2db1848a9c151' 
  AND token = 'xCc1z9SKw6leUQpTriPYo5je3c/7s+ox8J5iDgRq9nc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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