SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d31698eca90c920788cb6e06fa1a9046c18bca5f3384bd7d66d3785b1855d79' 
  AND token = 'ThT8gY0RhUeH56P9Ur81/01Ta8yHT5FWLPcUIn1dec8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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