SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86c09b96a68a42ccb190d8afd2d6301240d73ade70796a1f8caeb310ccbc70c3' 
  AND token = '4SK9JTgAoSZVNmzdpFgJaVsXityREQiGCK3rhYs0Nos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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