SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28ae0f4858360d9e147e4091640f4bd1d3206afe494b6a3b3b91ed8ebd537c7b' 
  AND token = '7ba9fpkY5TC71i6jFNKJSYhWI1Ja+awgngv6oYBizNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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