SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9672e165d6dca387acf3f4f5013e5b81b91efd5d174ebfbc3326d930927a3b70' 
  AND token = '6RkWYaRmg5KMuSZAIABChd4A0wl7cEzT39AKmhoPAHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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