SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b58be4f3ed3893fc9fd360dc54a571d92e88c9768a923f861efe5486d7afe2c' 
  AND token = 'zF/Ot6+q+74/FvlyJ9wPRSKkHnnnGWGdG1LZ9bug2Vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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