SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8644fb7bf25f5b78cb22147e759304f1fc70594452a820a22aadd2f286f93dc8' 
  AND token = 'N3DWTaRBIE5OlxH6naTyD2rPVAj4kIll41mLvucs92c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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