SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcf955ff9abf72253ed4c0c985e587553703e2eb82a300a414efe8862b8bf7b6' 
  AND token = 'fgMSUr4Ws5euSsX2sgCEtM8wEbOGO6e3rKVg8JUjhBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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