SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae50a3b791063780584e50eee94baecd8df58095aff51eac93ec6153d2b98351' 
  AND token = 'b5OGwHwy15q3L/60aGrACufKqKZSwDqfOLg8gxYtmPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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