SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd81faf5a57364a14c4ded6da476148982fefdec37b5b0d99233fd6b34ee498e2' 
  AND token = '+S6/1h3pGhYKeZ5JVfOGrPO99Q2AsmEYhpV/FQ+CR5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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