SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a50f2a5a6ce5c4e71848dc9879066f8d1a13ed68816a747e26f003ff9542747' 
  AND token = 'maQpD6xnxDmd65JgkXLabzzwpxsNnPcX0Rfaoxg5ZSE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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