SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd91498c91dae43f9be017da4b4a87225931d56a013d6f5ae9bf605b74a897e89' 
  AND token = 'JYKjJKpZmRV2QA9QH3/eNqF6JXsLtlQQCwvx7FTGkhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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