SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e1b2b99a98435b017103603af192ae0841669ac4df0004587ad03a0ac1f57c1' 
  AND token = 'IOE225ZArzuJQJzK2EhJswF2qRPccqHz5W3tKHWRpCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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