SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a875a075c73fe87607a7e9b8835fdf45c2cebe5ec7c796c033725b2d0938cbf6' 
  AND token = 'FcdyOZAmA67peJPQqvvVS7VYcRL6aeG/qJO0zWfFfgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}