SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c211b1ae581bd7031c64767a9d97fc3c3251b0ebf29bfd4fca33fb85ad4359d1' 
  AND token = 'VU8zAJf9GxsqdY1gXMDP+5siCTghKvInW1krA/etnGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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