SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2c037c6f983634cd095d4f2efb8f502a5f7eb758e4f105d9d5e5b9e005f46a2' 
  AND token = 'LaNi+/hoiZznvJDMrzARLBh8omHktmxIURTQgrAHPTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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