SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e9c51e20aa42b5ececa2f4488c7a481c1eb0e6217c6f816d172deb34bac6f2c' 
  AND token = 'KpX3RGf7cCg5szQgNeHbYkF/ZUlHOxNCrJZjiBKJjvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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