SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c06c57b7828e40ba055fb68d396ececc8564b043fc85f08e7bb8655ee0547c92' 
  AND token = 'n3GaZMHhTGfPDCXbs50y4NRbCetYmtMgXVaLsZly89o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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