SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb9de20b3eb6d1073555c03ed567a04f0f51db01d79322fa94af6e11326fee71' 
  AND token = 'CJMNpygUNW4bRePyyHs/Y1Uf+z/d1tUlEgWFV8wWlG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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