SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76e64a3d51a6fb81cdd6387f7207ba35224893e0e18266c8fc91275eddb6b504' 
  AND token = 'Z6Pv79w9pT6NBDrQKhuLdzISWlUYTaBS1+VfN5Z5e2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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