SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '566bb3277dcaba8386f76182e39530b080b5f2492f185e0352c77e37e73ec04e' 
  AND token = 'g29gkARZU/NyahdOgwBRcGYYhj2g4mgZ5i7ZhkMdoYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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