SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9420c3381e49cb0dfc1de318bf6a4e272b28abe08ed937fc6f5e98706a08257' 
  AND token = 'fBUS4/rIOw4ZdNWk2shZJKbgSYX7Taz6DDvXD9ASPnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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