SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7ddddfe82855d847d2534aa49b7b4121b0be51bdf4c601f6d4995b1f7dc3e95' 
  AND token = '6nT8I4NsK3uO6DIfwrFV/lOgUDj4Mz4BpHMlEbOChjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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