SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b3d8891af5837af02053b4ddbf9748eb6f2ef65242a35c8d2176460e49691df' 
  AND token = 'hi+ewcvdqbBvBgRY3xzcEUEIrGJcT+IStZpx3hWSMOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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