SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5498a2287a6880ee623c4f7e3306a2fda6c0c3fddb4486f049192d11cdac2b27' 
  AND token = 'KquFfKufmW7hLZRjM/Sp2FsrQ5S++c/wT8ZvSCywFA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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