SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '333a45265125ce7cecc8a5a22adbf5fbc6969b63a97173419af22c8bb1784bed' 
  AND token = '9YB17WEusa1LqO8X8Vd6WZHSrluj8J267kO+J5PkkOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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