SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c5d3635a10cbc826facbc5b65366e686093a0138c092a64ab53c0fe5a9ef38c' 
  AND token = 'xlOn0+DIF1QO+5XslfLtAzLH+OITGxyfHHjp/6ahZ2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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