SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f5a733a1bcd1a52e2ace491d0a677e7ce1a93438d0977a5c72c0c64da412feb' 
  AND token = 'uEBxe6F2lF3LbkGyRfXODK0r2uAUdgA/ApauWeGspiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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