SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6911dbc508c046bde58b2be0aaa776406840e86bddaee74341f33e9a62eac147' 
  AND token = 'yXOqqLlFmUfoqEUqdq/1n7QzufIXc8idJuPmUxQrrrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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