SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f363ba7be21a707770990ea3706924ae22530c5609096e7151325fa7058c914' 
  AND token = 'qtySLjS8socfYLt7GFyeX+rwli+GuAKPshjMrvuv6PA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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