SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '664fdf78a11062c0e3b176694c8b9d14e6e794cab40597ce38519d92fec4f433' 
  AND token = 'TUy8hKYZgKAPyis1kQYbHJvqLkw0vkLYw/1kCzIIXX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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