SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f018a83b5ae7430cd5dc428720750cbe73aa95b54d7940646743f5f6c137482' 
  AND token = 'auSBtpanxdVVPhvU+6ZQQspWGoW6eOgG7oabGbRl0aM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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