SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4972e6d7f65415a03c3ab5e265d981fcc00a22226c74ea0bc4b26fadff063939' 
  AND token = 'XRG++anuEK9Xnk4zXjE4J+KIBwU+d8ClKm/4hJKCSL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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