SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67a3e5149c68394cb3630f1a39b4c4d4f906ddc26b23f0442682f39fa1f50e5f' 
  AND token = 'x+qrXHWvMiKhqJ+C7Hmtl94XurxVt2b7ZpLLRDTzqhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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