SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34b1d7fa988bf71184d2c752f9d251487d1426e467c9e309d31c373cfb0e5953' 
  AND token = 'u4ERN18/Lp7JQBqy+vT7SYLaJo42D2aKzC2gxjecJAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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