SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '619ef595f03a73bfe23e7a514adf5f19f93e4a9c57d682c2e32000d802697781' 
  AND token = '78vd++g/pmjBzgS4VLoaYsbNHsmx0oGbW9h5Wxi3VHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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