SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f15412ff4e90319bdc18854bd3f449ae6147a6a02835199efe672fea8f450777' 
  AND token = 'hJFlOPUjhPMAjTf3zvo5VsMK76veTq2EYYvLXXOAH9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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