SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '820d8eee176423b8184f03d845ab1da953a62ccca9defdb74c6a296bb019cbbc' 
  AND token = 'jN6pVtzq2r5m9cgyNGjjNKIPdZ8dln0z+hY9FgmKmMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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