SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6925a0784bf4d6e9d96eef05054d3c8279c682ed950225a5cdc6e290832c07ee' 
  AND token = 'MOUcMUNuRN8HBnzpJgVflnkoLCtRJY8Y9jLl1bUb31Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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