SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab8a9810a61eab158f0da725cb766105272f183fa699c202dd9f2bfb9152933a' 
  AND token = 'NcvbfvByVAfvHUvuU2kxSbeLVl1YAnsywsNvuGYq5FU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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