SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ff7dc85b2e055f9b3046d1288b080ade3435cb43184611089d0ece381ce9aaa' 
  AND token = '1AEWL4wjdvZ7vCWRgTvfmcukl7mfzoQyqrv0tmd5nSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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