SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb3e81873c2b843d9d917e6a303ecec8e5b5c5a2b066c255f6bad436a5f010b5' 
  AND token = '8kRDHkuwSCRVHUKlfaMpWDbYNwfW8yMNkvEG8NBQTTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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