SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17dc0a4015e309f9a2079fcb7bd16c4e9e941fab63bbc908215d5d05bc9c0889' 
  AND token = 'BTYo7dLFoCFo1qLlgOSM7hVH2LFJYeVrwl+/3xR0rBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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