SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f0747ba79fd824fcd5e5abd4f80dc1cffaa9963ddfa1d1bb414ca2dc10b399b' 
  AND token = 'xjun2TkmD467+Hv58piIVhwv6m2nJPqFv6GDEHzJFlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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