SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '405068e790dbcc69879bc6f7bf541d8926188210d15ab19b00e06002de95f3d6' 
  AND token = 'iZTcHsUwzb+bbZx5RKIDIKLNq8M18FkPYNOipFMXpoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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