SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a0d9a2c847556799826fb719a43588492c91521b5d3f7459afe32d413545241' 
  AND token = '/TgjSrieeCphvIMr9DFc+JDB6ldO1m6QuKzHOdwC5DQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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