SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df29135f189412cab975cdfa883b2ec6e0f32fbc0cc78871c77dff2e371cb145' 
  AND token = 'jlZ4eqhy3USc9JZUMQGqBQzzWRD6bRB9mQZHBwmWPVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}