SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4840b84ff616caea79a28f1a2043bc4adaccf9ed7c978009199d2ed480425176' 
  AND token = 'eUbFGSDhOB3Q5wfuPiB+nk5YUTYjIRu6Quw4FbfAu6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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