SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a16f15731faa3a590b5e6f3cf8b37e3dc62f8d0e6b726c182893cf6d630849d' 
  AND token = '/QGfATqIFUY/H4kFg9BJ/Etw/HFC1txbE2h3gIWF5gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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