SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89e2676b6ccae7fa4b87f96874f11d3a381edc4536c87f0969e4f000d2c35424' 
  AND token = 'HmFbYNTF5rCnJv7uHzHNeaq7qvr4tMbU+0BZxVpUaxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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