SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ab0db4fe9f8404997bbc868f5e2513e9ba88083df7535a974cd1db2fab61a09' 
  AND token = '/71CumgZj0nsOaeNAudmpcJKLShBvVRrBK+NCP+rZ1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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