SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a3a8912c57c8736b0517b48b508d3a07a7c95dae6d04fc9c4b3896271956deb' 
  AND token = 'TZv3V+zp5GPrRa1+qtBVEfZKKnwr+yCBv4kZ3SuN+nw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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