SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b54c82bea07e9cd0bafda6052c783bbbadf9091687fe5ace54f3fbe09a4a107' 
  AND token = 'DPvrxj8ilbFQLDpya4kf0dE6fjOvQpwDw2u5TMlUnJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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