SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a267b5682a69ee7c6ea96898ba4890ce8381bfc94ab73f3f84c3e6b783e3d4f9' 
  AND token = 'ssXO+/uPZLE2lt/OMxCReB+JheKVvxqUVS429yDbhHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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