SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '299a02c24aaafef76da5b31802ebba2e9dbdd9b623477c2e0800b2632168833a' 
  AND token = 'ut9XUhF8PmP1EJ77+k1v1W2EhmrDKReDrp5D1TrZcFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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