SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02408c347e47b37eef91bbd377a5173b98d3dfb4a82e7399afd9a0e634933179' 
  AND token = 'Ly5OqwHzwLBaj4X42C+vXnOkrokHmWceLDdc/CBDctE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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