SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85e7c430bebc7600f875df0f9ed3bb80a659a44422ebe95f3efaa807ef8df456' 
  AND token = 'e0SMChwkLf8zo9aR8ebnLqSopgq2Th+cIgXxhGEs2w0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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