SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c55eef33faab05014538d90762e7f3dd3304ad347dabc85d950453c4c8b2ef66' 
  AND token = 'RT+e7wHZeoCDlv7DeGAWsAuvnHsMU0ovqI584tz5hOw=' 
  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"
    }
  }
}