SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6573992a45f654c70473996b1be8b5670f96339137903800f5588e4e7b86d0d1' 
  AND token = 'toQlkGxg1QQa7UQHzZkhG1CwuSPRWab3fxSFpMCORvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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