SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dda887c30e3adb7bab801ab3ef431802e76b186c5ed626baf369a4600cb9a83' 
  AND token = 'tEPSg72KWXjs71aZsJvhwRNzhs0ZUXJpUShRJ9H5GDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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