SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3aeaa2d3c12bba320180ae8fb2bbd652e96d6843dd2980b295c112db649756a2' 
  AND token = 'IxOjTgaM5I3UYXuNz8tjoORp94Rd1inxm02yKnZwGjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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