SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '832e6b92b2be74c635b4ebf5c50f4f9758a14a2155967346e90f38fe203f59b4' 
  AND token = 'lQqixxg8T4nKDnUnDAQFPLcT4vKFllupnWt2iSSyCnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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