SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '855d2aa9847599ea72d8e2bb4d91416b3246c6a28b67bc0b8b048ad7d2037e0b' 
  AND token = '64Tkuqc6NUQwzHtvPzj+IsQXs+3ENjsCzBN3wMXpoV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}