SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6e2a6416e064741851dceedc2620435479e0e5911bd6161df6002e5606c9f60' 
  AND token = 'sLsXWZ+Pvbu/4DO9iAITGBkHf8cWZ/9qWdOpZ1esnfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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