SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16dd97bc50d0538322de423a4b8d1f84b3191dea7aa0265804522b29ce4ca2c0' 
  AND token = 'A/Ig4IEs3kjpFm8Ppbar/p/aN9dXBhCze1ms+wg5AKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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