SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1400f2789cf291a3acd13832f14fdb9669ac433f53ad487d347955b32ab085c8' 
  AND token = 'LxYRtKbAITb7KKJgEtUnprfvJ6hKRKZuOzxrxnY29ek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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