SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '292098d996e4c0333ff8e031bfddf7b55ae70c87681f09d3d34d91bd009d1a75' 
  AND token = 'DOpPWpYH9LK7ySULksGszv4PW9p9GKCPREL8bhOtvS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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