SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2013054570f56348de968d5639ed82122c65336a8366a58efb5fea3184dc54a' 
  AND token = 'n97mSTnt+fFdrNtPEi2NsGou0VDhxSeYbiSYmFOLRX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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