SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2f8156d341a930ba606b414906f878cf526b35d0fd307eaabbad17c41ce0446' 
  AND token = '4STd6GD/0zz/Rz4/aNgVyOE9GnVKz12uNKPNUxiliBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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