SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9723b9c3f7eb761b314f631d8acd198cc4a37c839d8c4b47e14b79aaa805db58' 
  AND token = 'EhpBBZWvVLZg7wAUy+sjjJqwu19E6FYU66fQMdGBbdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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