SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd229469140a53556a64414ee84b4d6751087c55435318c83f66ad547d4d24ef' 
  AND token = 'vU/gWZlFPuPzwmMm1nUiPhE238aB9Y9YVFZzwWNYS6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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