SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b498d3252f5ad4a21cf8fbfbef27bc700c0dbf69c04734f138f35ed3120e712a' 
  AND token = 'HXCbkIp2iI+FYdsmYiPzsWDijxaQILAQBvsUmv0dt4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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