SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a28cb29a406a35bbfaea308905fc361f4559e68ea9f50e895bb46434e6038e0' 
  AND token = 'Hh9Cpp9HmA9flrgdqfDFrCGXYkDEOf0fuJnMN7HjPSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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