SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ef702ebcb8d337fd25a645ec07615dd19d1ac2d9ec9419bfd7939153cbb4803' 
  AND token = 'NqQfe0aRNem48B2sPtIovD6n983Ao/zNUFhJkWUqmx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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