SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c0e1872577f5e68bda8556de26cd9f24e336d5a5f7bf2418aa499bff9138476' 
  AND token = 'ZRk8NTLnXJMTQayQFXjK6QtBViTOojAshMw9eM3CmAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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