SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8046f9900a8682bad50891d068cd520a3aee4315f8b89c5780a382d59d4610f' 
  AND token = 'gWWo7MIaPWpZsPKhTBpNeFKUYnXsgoui1fkGcgQC0qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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