SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da4445a5a46fdf2f249027e7e51e1d60e949827765af4131cac2394c737fd546' 
  AND token = 'YgxlLzg+fUyEk7KK9E1vR7FXZtDCmyv8SnBVhq8XooI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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