SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f121fbec3e2ffbee08ab5cb8efed1462878fbadf385dd3575661e5f1716ca7b5' 
  AND token = 'yhrbo70KBir4D9CdxO28fzTLmVfgxCurqlJ97bvkRqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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