SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ee43a93aef988dad6f9602555ea762b0ffb1c578cb96b2ee05d5d5a1bad55f2' 
  AND token = 'WpUsX7Wjh9OyE5IteNCr59IXhxlP6zxvLSW9hmMClSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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